System and method for packet information indication in communication systems

ABSTRACT

A wireless device is described that may selectively include resource allocation information in a frame to be transmitted to one or more other wireless devices. The resource allocation may indicate channel/sub-channel assignment for each wireless device. The wireless devices may each utilize this received resource allocation information to determine the appropriate segment/sub-band of the transmission that is intended for their receipt/consumption. A first signaling field (e.g., HE-SIG-A) may indicate whether the resource allocation information is present in a second signaling field (e.g., HE-SIG-B) of the frame. For example, a single bit may be toggled to indicate the presence of the second signaling field and therefore the presence of the resource allocation information. Alternatively, multiple bits may be used to indicate the length of the second signaling field (e.g., a length of zero indicates the absence of the second signaling field and accordingly the absence of the resource allocation information).

RELATED APPLICATION(S)

This application is a continuation of application Ser. No. 14/836,749,filed Aug. 26, 2015, which claims the benefit of U.S. ProvisionalApplication No. 62/050,072, filed Sep. 12, 2014, each of which is herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

The present disclosure provides communication techniques for use inOFDMA and MU-MIMO type multi-user simultaneous transmissiontechnologies, and with applicability to other wired or wirelessmulti-user simultaneous transmission technologies.

BACKGROUND

Today, wireless local area networks (WLANs) are widely used forcommunications between various computer devices and for Internet access.A prominent WLAN technology is known as WiFi, which allows electronicdevices to network, using the 2.4 and 5 gigahertz bands. The term WiFirefers to any WLAN product that is based on the Institute of Electricaland Electronics Engineers (IEEE) 802.11 standards.

In 1999, IEEE 802.11a and 802.11b standards were released for WiFinetworks. The 802.11a protocol can support data transmissions of up to54 Mbps, whereas the 802.11b protocol has a longer range but maxing outat 11 Mbps data transmission speed.

In 2003, IEEE introduced 802.11g as a new WiFi standard. The 802.11gprotocol was designed to operate at a maximum transfer rate of 54 Mbpswhile allowing for a longer range.

Subsequently, the adoption of 802.11n by IEEE, sometimes calledWireless-N, brought about the ability to transfer data up to 300 Mbps,and incorporated multiple wireless signals and antennas to supportmultiple-input and multiple-output (MIMO) technology. The 802.11nprotocol allows data to be transmitted on both 2.4 GHz and 5 GHzfrequencies.

The latest WiFi technology from IEEE, i.e. the 802.11ac standard,introduced advancements in dual-band technology, which allows data to betransmitted across multiple signals and bandwidths for maximumtransmission rates of 1300 Mbps with extended range and nearlyuninterrupted transmission.

As WiFi technology continues to advance, multi-user simultaneoustransmission techniques, such as Orthogonal Frequency Division MultipleAccess (OFDMA) and Uplink (UL) Multi-User MIMO (MU-MIMO), are candidatesfor improving wireless network efficiency. Using these techniques,multiple stations (STA) can be allocated within a frame. These STAallocations require a communication of resource and packet informationby an access point (AP) for use by each STA.

The approaches described in this section are approaches that could bepursued, but not necessarily approaches that have been previouslyconceived or pursued. Therefore, unless otherwise indicated, it shouldnot be assumed that any of the approaches described in this sectionqualify as prior art merely by virtue of their inclusion in thissection.

SUMMARY

The present disclosure is directed to systems and methods for packetinformation indication in communication systems as shown and describedherein. In particular, a wireless device may selectively includeresource allocation/scheduling information in a frame to be transmittedto one or more other wireless devices. The resourceallocation/scheduling may indicate channel/sub-channel assignment foreach wireless device. The wireless devices may each utilize thisreceived resource allocation/scheduling information to determine theappropriate segment/sub-band of the transmission that is intended fortheir receipt/consumption.

In one embodiment, a first signaling field (e.g., HE-SIG-A) may indicatewhether the resource allocation/scheduling information is present in asecond signaling field (e.g., HE-SIG-B) of the frame. For example, asingle bit may be toggled to indicate the presence of the secondsignaling field and therefore the presence of the resourceallocation/scheduling information in the frame. In one embodiment,multiple bits may be used to indicate the length of the second signalingfield. In this embodiment, a length of zero indicates the absence of thesecond signaling field and accordingly the absence of the resourceallocation/scheduling information.

In some instances the transmission of resource allocation/schedulinginformation may be avoided to reduce overhead and/or superfluousinformation. For example, in single user transmissions, resourceallocation/scheduling information may be unnecessary as the channel willnot be subdivided. In another example, resource allocation/schedulinginformation may not be needed for responses to a trigger frame (i.e., aframe that previously provided resource allocation/schedulinginformation) as the transmitter of the trigger frame is already aware ofthe resource allocation/scheduling information.

The aforementioned aspect of the present disclosure and other aspectsare substantially shown in and/or are described in connection with atleast one of the figures, as set forth more completely in the claims.The above summary does not include an exhaustive list of all aspects ofthe present invention. It is contemplated that the invention includesall systems and methods that can be practiced from all suitablecombinations of the various aspects summarized above, as well as thosedisclosed in the Detailed Description below and particularly pointed outin the claims filed with the application. Such combinations haveparticular advantages not specifically recited in the above summary

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a network, including a wireless area network (WLAN)having a plurality of stations in wireless communication with an accesspoint;

FIG. 2 presents components of a WLAN device for use in the WLAN of FIG.1;

FIG. 3 presents a physical layer (PHY) frame for use by the WLAN of FIG.1 when operating according to the 802.11ac standard;

FIG. 4A presents an OFDMA and MU-MIMO type resource allocation diagramof a PHY frame;

FIG. 4B presents an OFDMA type resource allocation diagram of a PHYframe;

FIG. 4C presents a MU-MIMO type resource allocation diagram of a PHYframe;

FIG. 5 presents a PHY frame having a PHY header with four (4) possibleSIG fields and a HE-TF-B field, according to one implementation of thepresent disclosure;

FIG. 6 presents a PHY frame having a PHY header with four (4) possibleSIG fields, according to one implementation of the present disclosure;

FIG. 7A presents a PHY frame having a PHY header with three (3) SIGfields and a HE-TF-B field, according to one implementation of thepresent disclosure;

FIG. 7B presents a PHY frame having a PHY header with two (2) SIGfields, according to one implementation of the present disclosure;

FIG. 8 presents a PHY frame having a PHY header with three (3) SIGfields, according to one implementation of the present disclosure;

FIG. 9 presents a PHY frame having a PHY header with four (4) possibleSIG fields and a common HE-STF/LTF1 field, according to oneimplementation of the present disclosure;

FIG. 10 presents a PHY frame having a PHY header with three (3) SIGfields and a common HE-STF/LTF1 field, according to one implementationof the present disclosure;

FIG. 11 presents a flow diagram of a method for use by a station of FIG.1, according to one implementation of the present disclosure; and

FIG. 12 presents a flow diagram of a method for use by a station of FIG.1, according to one implementation of the present disclosure.

DETAILED DESCRIPTION

The following description contains specific information pertaining toimplementations in the present disclosure. The drawings in the presentapplication and their accompanying detailed description are directed tomerely exemplary implementations. Unless noted otherwise, like orcorresponding elements among the figures may be indicated by like orcorresponding reference numerals. Moreover, the drawings andillustrations in the present application are generally not to scale, andare not intended to correspond to actual relative dimensions.

FIG. 1 illustrates network 100 including wireless area network (WLAN)110 having a plurality of stations (STA) 104/106/108 in wirelesscommunication with access point (AP) 102. As shown in FIG. 1, AP 102 isalso in communication with computers 117/119 over wide area network orInternet 115. WLAN 110 may be a WiFi network, which is established usingany set of protocols, techniques, and standards, including protocols andtechniques presented herein. In particular, each STA 104/106/108 iswirelessly connected to AP 102 and communicates with AP 102 using anyset of protocols, techniques, and standards, including protocols andtechniques presented herein. AP 102 is also connected to Internet 115either through a wired connection, such as DSL or cable, or through awireless connection, such as 3G or Long-Term Evolution (LTE). As such,each STA 104/106/108 may also communicate with computers 117/119 overInternet 115 through AP 102.

FIG. 2 presents components of WLAN device 200, which may be any of AP102 and STAs 104/106/108, for use in WLAN 110 of FIG. 1. WLAN device 200may include a medium access control (MAC) layer and a physical (PHY)layer, according to any set of protocols, techniques, and standards,including protocols and techniques presented herein. In oneimplementation, as shown in FIG. 1, at least one WLAN device may beoperated as an access point device, such as AP 102, and the other WLANdevices may be non-AP stations, such as STAs 104/106/108. In otherimplementations, not shown in FIG. 1, all WLAN devices may be non-APSTAs in an ad-hoc networking environment. In general, the AP STA and thenon-AP STAs may be collectively or individually referred to as stationsor station, respectively.

With reference to FIG. 2, WLAN device 200 includes baseband processor202, radio frequency (RF) transceiver 220, antenna unit 230, memory 240,input interface unit 242, and output interface unit 244. Basebandprocessor 202 performs baseband signal processing and includes MACprocessor 204 and PHY processor 210.

In one implementation, MAC processor 204 may include MAC softwareprocessing unit 206 and MAC hardware processing unit 208. Memory 240 isa computer readable non-transitory storage device and may storesoftware, such as MAC software, including at least some functions of theMAC layer. Memory 240 may further store an operating system and othersoftware and applications for WLAN device 200. MAC software processingunit 206 executes the MAC software to implement various functions of theMAC layer, and MAC hardware processing unit 208 may implement otherfunctions of the MAC layer in hardware.

In one implementation, PHY processor 210 includes receive (RX) signalprocessing unit 212, which is connected to RF receiver 224, and transmit(TX) signal processing unit 214, which is connected to RF transmitter222.

TX signal processing unit 214 may include an encoder, an interleaver, amapper, an inverse Fourier transformer (IFT), and a guard interval (GI)inserter. In operation, the encoder encodes input data, the interleaverinterleaves the bits of each stream output from the encoder to changethe order of bits, the mapper maps the sequence of bits output from theinterleaver to constellation points, the IFT converts a block of theconstellation points output from the mapper to a time domain block(i.e., a symbol) by using an inverse discrete Fourier transform (IDFT)or an inverse fast Fourier transform (IFFT), and the GI inserterprepends a GI to the symbol for transmission using RF transmitter 222 ofRF transceiver 220. When MIMO or MU-MIMO is used, RF transmitter 222 andthe GI inserter may be provided for each transmit chain, in addition toone or more other portions of TX signal processing unit 214.

RX signal processing unit 212 may include a decoder, a deinterleaver, ademapper, a Fourier transformer (FT), and a GI remover. In operation,the GI remover receives symbols from RX receiver 224 of RF transceiver220. When MIMO or MU-MIMO is used, RF receiver 224 and the GI removermay be provided for each receive chain, in addition to one or more otherportions of RX signal processing unit 212. The FT converts the symbol(i.e., the time domain block into a block of the constellation points byusing a discrete Fourier transform (DFT) or a fast Fourier transform(FFT). The demapper demaps the constellation points output from the FT,the deinterleaver deinterleaves the bits of each stream output from thedemapper, and the decoder decodes the streams output from thedeinterleaver to generate input data for framing.

In one implementation, input interface unit 242 is configured to receiveinformation from a user, and output interface unit 244 is configured tooutput information to the user. Antenna unit 230 may include one or moreantennas for wireless transmission and reception of wireless signals.For example, for MIMO or MU-MIMO transmissions, antenna unit 230 mayinclude a plurality of antennas.

Turning to FIG. 3, FIG. 3 presents physical layer (PHY) frame 300 foruse by WLAN 110 of FIG. 1 when operating according to the IEEE 802.11acstandard. As shown in FIG. 3, PHY frame 300 includes PHY header 301 andPHY payload 321. PHY header 301 has a plurality of fields, includingL-STF 302, L-LTF 304, L-SIG 306, VHT-SIG-A 308, VHT-STF 310, VHT-LTF312, VHT-SIG-B 314, and PHY payload 321 includes data 322.

L-STF (Legacy Short Training Field) 302 and L-LTF (Legacy Long TrainingField) each may be represented by two (2) OFDM symbols that are used toassist WiFi receivers in identifying that an IEEE 802.11 frame is aboutto start, synchronizing timers, and estimating wireless channels. L-SIG(Legacy Signal Field) 306 is used to describe the data rate and lengthof the frame in bytes, which is used by WiFi receivers to calculate thetime duration of the frame's transmission. Any IEEE 802.11 device thatis capable of OFDM operation can decode L-STF 302, L-LTF 304 and L-SIG306. PHY header 301 starts with L-STF 302, L-LTF 304 and L-SIG 306, sothat even legacy STAs that do not support the IEEE 802.11ac standard areable to detect at least legacy parts (L-STF, L-LTF, and L-SIG) of PHYheader 301.

VHT-SIG-A (Very High Throughput Signal A) 308 and VHT-SIG-B (Very HighThroughput Signal B) 314, taken together, describe the included frameattributes, such as the channel width, modulation and coding, PHYpayload 321, and whether the frame is a single-user or multi-user frame.The purpose of VHT-SIG-A 308 and VHT-SIG-B 314 is to help the WiFireceiver decode the data payload, which is done by describing theparameters used for transmission. The IEEE 802.11ac standard separatesthe signal into two different parts, called VHT-SIG-A 308 and VHT-SIG-B314. VHT-SIG-A 308 is in the part of PHY header 301 that is receivedidentically by all receivers. VHT-SIG-B 314 is in the part of PHY header301 that is different for each multi-user receiver in case of down-link(DL) MU-MIMO transmission. VHT-SIG-A 308 is duplicated for each 20 MHzband, so that STAs can identify PHY header 301 by only checking theprimary 20 MHz band. It should be noted that in case of a single usertransmission, there is only one target receiver and, as such, there isno separate VHT-SIG-B for another receiver.

VHT-SIG-A 308 comes first in PHY header 301 and may take on one of twoforms depending on whether the transmission is single-user ormulti-user. Because VHT-SIG-A 308 holds rate information for decodingPHY payload 321, VHT-SIG-A 308 is transmitted using a conservativemodulation technique. VHT-SIG-B 314 may be used to set up the data rate,as well as tune in MIMO reception. Like VHT-SIG-A 308, VHT-SIG-B 314 ismodulated conservatively to assist receivers in determining the datarate of PHY payload 321. For example, VHT-SIG-A 308 and VHT-SIG-B 314may be encoded with the lowest Modulation and Coding Scheme (MCS) level.VHT-SIG-B 314 is designed to be transmitted in a single OFDM symbol. Assuch, VHT-SIG-B 314 has slightly different lengths depending on thechannel width.

VHT-STF (Very High Throughput Short Training Field) 310 serves the samepurpose as L-STF 302. Just as the first training fields help a receivertune in the signal, VHT-STF 310 assists the receiver in detecting arepeating pattern and setting receiver gain. VHT-LTF (Very HighThroughput Long Training Field) 312 consists of a sequence of symbolsthat set up demodulation of the rest of the frame and also the channelestimation process for beamforming. The number of VHT-LTF 312 symbolsvaries depending on the number of spatial streams carried on thepayload.

Data 316 holds the higher-layer protocol packet or possibly an aggregateframe containing multiple higher-layer packets. PHY payload 321, whichcontains data payload 316, immediately follows PHY header 301. Datapayload 316 is transmitted at the data rate described by PHY header 301.

Although PHY frame 300 may have some benefits, PHY frame 300 may not beappropriate for OFDMA type resource allocation, as described below. FIG.4A presents an OFDMA and MU-MIMO type resource allocation diagram 400for a PHY frame. As shown in FIG. 4A, four (4) different users areallocated within one frame duration. Payload for User 1 (404) andPayload for User 2 (406) are allocated in the primary 20 MHz band (401)in an OFDMA manner, which means Payload for User 1 (404) and Payload forUser 2 (406) occupy different frequency resources within the primary 20MHz band (401). Payload User 3 (408) and Payload User 4 (410) areallocated in the secondary 20 MHz band (402) in MU-MIMO manner, whichmeans Payload User 3 (408) and Payload User 4 (410) occupy the same timeand frequency resource, but are separated in the spatial domain usingmultiple antenna techniques. In the example of FIG. 4A, the PHY payloadfor each of the four users occupies a different resource, either in adifferent frequency or spatially separated, but shares at least aportion of the same PHY header. In particular, for uplink transmissions,where multiple different STAs transmit to the same AP, all STAs transmitthe same information in at least a portion of the same PHY header, suchthat the AP can decode the PHY header correctly, since the portion ofthe PHY header is shared by all STAs.

FIG. 4B presents an OFDMA type resource allocation diagram 420 for a PHYframe. As shown in FIG. 4B, four (4) different users are allocatedwithin one frame duration. Payload for User 1 (424) and Payload for User2 (426) are allocated in the primary 20 MHz band (421) in an OFDMAmanner, which means Payload for User 1 (424) and Payload for User 2(426) occupy different frequency resources within the primary 20 MHzband (421). Payload User 3 (428) and Payload User 4 (430) are allocatedin the secondary 20 MHz band (422), also in an OFDMA manner, which meansPayload User 3 (428) and Payload User 4 (430) occupy different frequencyresources within the secondary 20 MHz band (422).

FIG. 4C presents an MU-MIMO type resource allocation diagram 440 for aPHY frame. As shown in FIG. 4C, four (4) different users are allocatedwithin one frame duration. In particular, Payload User 1 (444), PayloadUser 2 (446), Payload User 3 (448), and Payload User 4 (450) are allallocated in both the primary 20 MHz band (441) and the secondary 20 MHzband (442) in an MU-MIMO manner (i.e., Payload User 1 (444), PayloadUser 2 (446), Payload User 3 (448), and Payload User 4 (450) occupy thesame time and frequency resource, but are separated in spatial domainusing multiple antenna techniques). Although shown in relation to a 40MHz channel (i.e., the combined primary 20 MHz band (441) and secondary20 MHz band (442)), this MU-MIMO technique may be performed in relationto any size channel (e.g., 20 MHz, 80 MHz, etc.).

Since signals from multiple STAs 104/106/108 are to be receivedsimultaneously at AP 102, each STA's 104/106/108 transmission timing hasto be synchronized. Also, signals from multiple STAs 104/106/108 need tobe sent within the scheduled resource to avoid packet collision betweenthe STAs 104/106/108. Even though different STAs 104/106/108 usenon-overlapping resources, at least part of the PHY header of each STA104/106/108 may be sent using the same or an overlapping resource, suchas legacy fields of L-STF, L-LTF and L-SIG. As such, the portion of thePHY header sent using the overlapping resource must be the same for allSTAs 104/106/108, such that the combined signal can be decoded at AP102. To this end, AP 102 sends a scheduling information frame (e.g., atrigger frame) to all STAs 104/106/108 prior to simultaneoustransmissions by the STAs 104/106/108. The scheduling information framemay satisfy multiple purposes by setting a reference time forsynchronization, providing information on resource allocation, andproviding information as to how to encode the portion of the PHY headertransmitted using the overlapping resource.

Since AP 102 provides STAs 104/106/108 with scheduling or resourceallocation information before STAs' 104/106/108 uplink (UL)transmissions, the resource allocation information in the PHY headerportion of STA's 104/106/108 UL transmission is redundant and serves nopurpose as AP 102 already knows the resource allocation information thatAP 102 originally transmitted to the STAs 104/106/108. In fact, STAs104/106/108 may not use a different resource allocation than the oneindicated by AP 102, since that can cause collisions with ULtransmissions from other STAs 104/106/108. As such, STAs 104/106/108must follow the exact resource allocation provided by AP 102.

Therefore, using PHY frame 300 will result in each STA's UL transmissionto include the same resource allocation portion that is received from AP102 and which is already known by STA 104/106/108. Thus, as noted above,including the resource allocation information in the PHY header of eachSTA's 104/106/108 UL transmission will increase signaling overhead andis redundant. In one implementation of the present disclosure, the PHYheader includes at least two signaling (SIG) fields, which are encodedseparately. The first encoded SIG field includes a resource allocationindication (RAI) to indicate whether or not the other encoded SIGfield(s) includes resource allocation information. STA 104/106/108 doesnot include the resource allocation information in the PHY header if areceiver of a frame, e.g. AP 102, has access to the resource allocationinformation, such as UL OFDMA and single user full band transmissions.However, STA 104/106/108 includes the resource allocation information inthe PHY header if the receiver of the frame does not have access to theresource allocation information, such as DL OFDMA or single user partialband transmissions. For example, in case of UL MU simultaneoustransmission, every STA that participates in the transmission needs toset the RAI in the first encoded signaling (SIG) field to indicate thatresource allocation information is not included in the other encoded SIGfield(s). In another implementation, the PHY header includes a singleSIG field, such that the other encoded SIG fields are completely omittedif the receiver of the frame has access to all information that would beincluded within these omitted SIG field(s).

FIG. 5 presents PHY frame 500 having PHY header 501 with four (4)possible SIG fields 504/506/510/514 and HE-TF-B field 508, according toone implementation of the present disclosure. As shown in FIG. 5, SIGfields include L-SIG 504, HE-SIG-A 506, HE-SIG-B 510 and HE-SIG-C 514,where HE stands for high efficiency. In the implementation of FIG. 5,HE-SIG-A 506 includes an indication to indicate to a receiver whetherHE-SIG-B 510 is included in PHY header 501 or not, where HE-SIG-B 510includes resource allocation information. As such, HE-SIG-B 510 isincluded in PHY header 501 only when HE-SIG-A 506 indicates thatHE-SIG-B 510 exists in PHY header 501. As shown in FIG. 5, PHY header501 also includes L-STF/L-LTF 502 and L-SIG 504, which may be the sameas L-STF 302, L-LTF 304 and L-SIG 306, respectively, in PHY header 301of FIG. 3.

In the implementation of FIG. 5, HE-SIG-A 506 may include informationrelating to proper channel deferral and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, BSS Color, group ID and/or partial AID/BSSID of target STAs,GI (Guard Interval), and frequency domain tone spacing in the event thatthere is more than one frequency domain tone spacing used in the frame.HE-SIG-A 506 may also include an indication as to whether HE-SIG-B 510exists in PHY header 501. In one implementation, HE-SIG-B 510 may have avariable size and HE-SIG-A 506 may indicate a length of HE-SIG-B 510.For example, if HE-SIG-A 506 indicates that the length of HE-SIG-B 510is zero, PHY header 501 will not include HE-SIG-B 510 (i.e., this lengthserves as the indication that HE-SIG-B 510 is not present in the frame).However, if HE-SIG-A 506 indicates that the length of HE-SIG-B 510 is anumber other than zero (e.g., greater than zero), PHY header 501 willinclude HE-SIG-B 510 having a length indicated by the number provided inHE-SIG-A 506. In another implementation, HE-SIG-B 510 may have a fixed,pre-established length and a single bit in HE-SIG-A 506 may indicatewhether or not PHY header 501 includes HE-SIG-B 510.

HE-SIG-A 506 may be encoded in a predetermined channel bandwidth, e.g.20 MHz, and may be duplicated at every predetermined channel bandwidththat the frame occupies. Also, channel estimation and decoding ofHE-SIG-A 506 may rely on L-STF/L-LTF 502. HE-SIG-B 510 may include theresource allocation information for each scheduled STA, which mayinclude mapping information between allocated sub-channel andcorresponding STA. HE-SIG-B 510 may be encoded using an entire bandwidththat is indicated in HE-SIG-A 506. In some embodiments, HE-SIG-B may berepeated across separate sub-bands of the entire bandwidth. For example,duplicated copies of HE-SIG-B may be repeated in 20 MHz segments of thefull channel bandwidth. In another example, HE-SIG-B may be partiallycopied in a set of sub-bands. For example, a first 20 MHz sub-band mayinclude a first HE-SIG-B, a second 20 MHz sub-band may include a secondHE-SIG-B, a third 20 MHz sub-band may include the first HE-SIG-B, afourth 20 MHz sub-band may include the second HE-SIG-B, etc.

For proper decoding of HE-SIG-B 510, PHY header 501 includes HE-TF-B508, which refers to STF/LTF for HE-SIG-B, and appears before HE-SIG-B510, as shown in FIG. 5. In the event that PHY header 501 does notinclude HE-SIG-B 510, as indicated by HE-SIG-A 506, HE-TF-B 508 willalso not be included in PHY header 501.

HE-SIG-C 514 may include per-STA frame information, such as MCS level,coding scheme, and use of Space-time block coding (STBC). In oneimplementation, HE-SIG-C 514 may be encoded per each allocatedsub-channel, and may utilize HE-STF/LTF 502 for channel estimation anddecoding.

FIG. 6 presents PHY frame 600 having PHY header 601 with four (4)possible SIG fields 604/606/608/612, according to one implementation ofthe present disclosure. As shown in FIG. 6, SIG fields include L-SIG604, HE-SIG-A 606, HE-SIG-B 608, and HE-SIG-C 612. In the implementationof FIG. 6, HE-SIG-A 606 includes an indication to a receiver whetherHE-SIG-B 608 is included in PHY header 601 or not, where HE-SIG-B 608includes resource allocation information. As such, HE-SIG-B 608 isincluded in PHY header 601 only when HE-SIG-A 606 indicates thatHE-SIG-B 608 exists in PHY header 601. As shown in FIG. 6, PHY header601 also includes L-STF/L-LTF 602 and L-SIG 604, which are the same asL-STF 302, L-LTF 304, and L-SIG 306 in PHY header 301 of FIG. 3.

In the implementation of FIG. 6, HE-SIG-A 606 may include informationrelating to proper channel deferral, and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, BSS Color, group ID and/or partial AID/BSSID of target STAs,GI (Guard Interval), and frequency domain tone spacing in the event thatthere is more than one frequency domain tone spacing used in the frame.HE-SIG-A 606 may also include an indication as to whether HE-SIG-B 608exists in PHY header 601. In one implementation, HE-SIG-B 608 may have avariable size and HE-SIG-A 606 may indicate a length of HE-SIG-B 608.For example, if HE-SIG-A 606 indicates that the length of HE-SIG-B 608is zero, HE-SIG-B 608 will not be included in PHY header 601. However,if HE-SIG-A 606 indicates that the length of HE-SIG-B 608 is a numberother than zero, PHY header 601 will include HE-SIG-B 608 of the lengthindicated by the number in HE-SIG-A 606. In another implementation,HE-SIG-B 608 may have a fixed, pre-established length and a single bitin HE-SIG-A 606 may indicate whether or not PHY header 601 includesHE-SIG-B 608.

HE-SIG-A 606 is encoded in a predetermined channel bandwidth, e.g. 20MHz, and is duplicated at every predetermined channel bandwidth that theframe occupies. Also, channel estimation and decoding of HE-SIG-A 606may rely on L-STF/L-LTF 602. HE-SIG-B 608 has the resource allocationinformation for each scheduled STA, which may include mappinginformation between allocated sub-channel and a corresponding STA.HE-SIG-B 608 may be encoded using an entire bandwidth that is indicatedin HE-SIG-A 606 or may be encoded across multiple sub-bands of thechannel in duplicated, non-duplicated, or partially duplicated parts asnoted above. Unlike the implementation of FIG. 5, PHY header 601 of FIG.6 does not include a HE-TF-B field and, thus, there is less overhead inPHY header 601 compared to PHY header 501. In the implementation of FIG.6, for proper decoding of HE-SIG-B 608 with the absence of a HE-TF-Bfield, the receiver buffers the entire channel bandwidth of the receivedL-LTF 602 and after identifying the bandwidth of the frame, the receiverreutilizes L-LTF 602 information for the whole occupied bandwidth fordecoding HE-SIG-B 608.

HE-SIG-C 612 may include per-STA frame information, such as MCS level,coding scheme, and/or use of STBC. In one implementation, HE-SIG-C 612may be encoded per each allocated sub-channel and may utilize HE-STF/LTF610 for channel estimation and decoding.

FIG. 7A presents PHY frame 700 having PHY header 701 with three (3) SIGfields 704/706/710 and HE-TF-B 708 field, according to oneimplementation of the present disclosure. As shown in FIG. 7A, SIGfields include L-SIG 704, HE-SIG-A 706, and HE-SIG-B 710. In theimplementation of FIG. 7A, HE-SIG-A 706 includes an indication to areceiver whether or not HE-SIG-B 710 includes resource allocationinformation. As such, resource allocation information is included inHE-SIG-B 710 only when HE-SIG-A 706 indicates that HE-SIG-B 710 includessuch information. As shown in FIG. 7A, PHY header 701 also includesL-STF/L-LTF 702 and L-SIG 704, which are the same as L-STF 302, L-LTF304 and L-SIG 306 in PHY header 301 of FIG. 3.

In the implementation of FIG. 7A, HE-SIG-A 706 may include informationrelating to proper channel deferral, and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, BSS Color, group ID and/or partial AID/BSSID of target STAs,GI (Guard Interval), and frequency domain tone spacing in the event thatthere is more than one frequency domain tone spacing used in the frame.HE-SIG-A 706 may also include an indication if HE-SIG-B 710 is presentin the PHY header 700 or includes resource allocation information.

HE-SIG-A 706 may be encoded in a predetermined channel bandwidth, e.g.20 MHz, and may be duplicated at every predetermined channel bandwidththat the frame occupies. Also, channel estimation and decoding ofHE-SIG-A 706 may rely on L-STF/L-LTF 702. HE-SIG-B 710 may includeper-STA frame information, such as MCS level, coding scheme, and/or useof STBC. If HE-SIG-A 706 indicates that HE-SIG-B 710 includes resourceallocation information, HE-SIG-B 710 field will have resource allocationinformation for each scheduled STA, which may include mappinginformation between allocated sub-channel and a corresponding STA.HE-SIG-B 710 may be encoded using an entire bandwidth that is indicatedin HE-SIG-A 706 or may be encoded across multiple sub-bands of thechannel in duplicated, non-duplicated, or partially duplicated parts asnoted above. For proper decoding of HE-SIG-B 710, PHY header 701 mayinclude HE-TF-B 708, which appears before HE-SIG-B 710, as shown in FIG.7A.

As shown in FIG. 7A, PHY header 701 may also include L-STF/L-LTF 702 andL-SIG 704, which are the same as L-STF 302, L-LTF 304 and L-SIG 306 inPHY header 301 of FIG. 3. HE-SIG-A 706 may include information relatingto proper channel deferral and overall frame format information, whichmay include channel bandwidth, basic service set (BSS) ID, BSS Color,group ID and/or partial AID/BSSID of target STAs, GI (Guard Interval),and frequency domain tone spacing in the event that there is more thanone frequency domain tone spacing used in the frame. HE-SIG-A 706 mayalso include an indication if HE-SIG-B 710 is included in PHY header701. In one implementation, HE-SIG-B 710 may have a variable size andHE-SIG-A 706 may indicate a length of HE-SIG-B 710. For example, ifHE-SIG-A 706 indicates that the length of HE-SIG-B 710 is zero, PHYheader 701 will not include HE-SIG-B 710. However, if HE-SIG-A 706indicates that the length of HE-SIG-B 710 is a number other than zero,PHY header 701 will include HE-SIG-B 710 of the length indicated.

HE-SIG-A 706 may be encoded in a predetermined channel bandwidth, e.g.20 MHz, and may be duplicated at every predetermined channel bandwidththat the frame occupies. Also, channel estimation and decoding ofHE-SIG-A 706 may rely on L-STF/L-LTF 702. HE-SIG-B 710 may includeper-STA frame information, such as MCS level, coding scheme, and/or useof STBC. HE-SIG-B 710 may have resource allocation information for eachscheduled STA, which may include mapping information between allocatedsub-channel and corresponding STA. HE-SIG-B 710 may be encoded using anentire bandwidth that is indicated in HE-SIG-A 706 or may be encodedacross multiple sub-bands of the channel in duplicated, non-duplicated,or partially duplicated parts as noted above. For proper decoding ofHE-SIG-B 710, PHY header 701 includes HE-TF-B 708, which appears beforeHE-SIG-B 710, as shown in FIG. 7A. In the event that PHY header 701 doesnot include HE-SIG-B 710, as indicated by HE-SIG-A 706, HE-TF-B 708 willalso not be included in PHY header 701.

FIG. 7B presents PHY frame 750 having PHY header 751 according to oneimplementation of the present disclosure, where HE-SIG-A 756 may includean indication to a receiver that a HE-SIG-B field is not included in PHYheader 751. As such, resource allocation information is included onlywhen HE-SIG-A 756 (or HE-SIG-A 706 of FIG. 7A) indicates that theHE-SIG-B is included in PHY header 751 (or 701). In FIG. 7B, L-STF/L-LTF752, L-SIG 754, HE-SIG-A 756, HE-STF/LTF 758 and Data Payload 760 maycorrespond to L-STF/L-LTF 702, L-SIG 704, HE-SIG-A 706, HE-STF/LTF 712and Data Payload 714 of FIG. 7A, respectively.

FIG. 8 presents PHY frame 800 having PHY header 801 with three (3) SIGfields 804/806/808, according to one implementation of the presentdisclosure. As shown in FIG. 8, SIG fields include L-SIG 804, HE-SIG-A806, and HE-SIG-B 808. In the implementation of FIG. 8, HE-SIG-A 806includes an indication to a receiver whether or not HE-SIG-B 808includes resource allocation information. As such, resource allocationinformation is included in HE-SIG-B 808 only when HE-SIG-A 806 indicatesthat HE-SIG-B 808 includes such information. As shown in FIG. 8, PHYheader 801 also includes L-STF/L-LTF 802 and L-SIG 804, which are thesame as L-STF 302, L-LTF 304, and L-SIG 306 in PHY header 301 of FIG. 3.

Unlike the implementation of FIG. 7A, PHY header 801 of FIG. 8 may notinclude a HE-TF-B field and, thus, there is less overhead in PHY header801 compared to PHY header 701. In the implementation of FIG. 8, forproper decoding of HE-SIG-B 808 with a HE-TF-B field absent, thereceiver buffers the entire channel bandwidth of the received L-LTF 802,and after identifying the bandwidth of the frame, the receiverreutilizes L-LTF 802 information for the whole occupied bandwidth fordecoding HE-SIG-B 808.

In the implementation of FIG. 8, HE-SIG-A 806 may include informationrelating to proper channel deferral, and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, BSS Color, group ID and/or partial AID/BSSID of target STAs,GI (Guard Interval), and frequency domain tone spacing in the event thatthere is more than one frequency domain tone spacing used in the frame.HE-SIG-A 806 may also include an indication if HE-SIG-B 808 includesresource allocation information and may also indicate the size ofHE-SIG-B 808.

HE-SIG-A 806 is encoded in a predetermined channel bandwidth, e.g. 20MHz, and is duplicated at every predetermined channel bandwidth that theframe occupies. Also, channel estimation and decoding of HE-SIG-A 806may rely on L-STF/L-LTF 802. HE-SIG-B 808 includes per-STA frameinformation, such as MCS level, coding scheme, and/or use of STBC. IfHE-SIG-A 806 indicates that HE-SIG-B 808 includes resource allocationinformation, HE-SIG-B 808 will have resource allocation information foreach scheduled STA, which may include mapping information betweenallocated sub-channel and corresponding STA. HE-SIG-B 808 may be encodedusing an entire bandwidth that is indicated in HE-SIG-A 806 or may beencoded across multiple sub-bands of the channel in duplicated,non-duplicated, or partially duplicated parts as noted above. For properdecoding of HE-SIG-B 808, the receiver needs to buffer L-LTF 802 valuefor the entire channel bandwidth of the received frame, as discussedabove.

In another implementation of FIG. 8, HE-SIG-A 806 includes an indicationto a receiver whether HE-SIG-B 808 is included in PHY header 801 or not,where HE-SIG-B 808 includes resource allocation information. As such,resource allocation information is included only when HE-SIG-A 806indicates that HE-SIG-B 808 is included. As shown in FIG. 8, PHY header801 also includes L-STF/L-LTF 802 and L-SIG 804, which are the same asL-STF 302, L-LTF 304 and L-SIG 306 in PHY header 301 of FIG. 3.

In this implementation of FIG. 8, HE-SIG-A 806 may include informationrelating to proper channel deferral and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, group ID and/or partial AID/BSSID of target STAs, GI (GuardInterval), and frequency domain tone spacing in the event that there ismore than one frequency domain tone spacing used in the frame. HE-SIG-A806 may also include an indication if HE-SIG-B 808 is included in PHYheader 801, and/or may also indicate the size of HE-SIG-B 808. In oneimplementation, HE-SIG-B 808 may have a variable size, and HE-SIG-A 806may indicate a length of HE-SIG-B 808. For example, if HE-SIG-A 806indicates that the length of HE-SIG-B 808 is zero, HE-SIG-B 808 is notincluded in PHY header 801. However, if HE-SIG-A 806 indicates that thelength of HE-SIG-B 808 is a number other than zero, PHY header 801 willinclude HE-SIG-B 808 of the length indicated.

HE-SIG-A 806 may be encoded in a predetermined channel bandwidth, e.g.20 MHz, and is duplicated at every predetermined channel bandwidth thatthe frame occupies. Also, channel estimation and decoding of HE-SIG-A806 may rely on L-STF/L-LTF 802. HE-SIG-B 808 includes per-STA frameinformation, such as MCS level, coding scheme, and use of STBC. HE-SIG-B808 may also have resource allocation information for each scheduledSTA, which may include mapping information between allocated sub-channeland corresponding STA. HE-SIG-B 808 may be encoded using an entirebandwidth that is indicated in HE-SIG-A 806 or may be encoded acrossmultiple sub-bands of the channel in duplicated, non-duplicated, orpartially duplicated parts as noted above. For proper decoding ofHE-SIG-B 808, the receiver needs to buffer L-LTF 802 value for theentire channel bandwidth of the received frame, as discussed above.

FIG. 9 presents PHY frame 900 having PHY header 901 with four (4)possible SIG fields 904/906/910/912 and common HE-STF/LTF1 908 field,according to one implementation of the present disclosure.

As shown in FIG. 9, SIG fields include L-SIG 904, HE-SIG-A 906, HE-SIG-B910, and HE-SIG-C 912. In the implementation of FIG. 9, HE-SIG-A 906includes an indication to a receiver whether HE-SIG-B 910 is included inPHY header 901 or not, where HE-SIG-B 910 includes resource allocationinformation. As such, HE-SIG-B 910 is included in PHY header 901 onlywhen HE-SIG-A 906 indicates that HE-SIG-B 910 exists in PHY header 901.As shown in FIG. 9, PHY header 901 also includes L-STF/L-LTF 902 andL-SIG 904, which are the same as L-STF 302, L-LTF 304 and L-SIG 306 inPHY header 301 of FIG. 3. PHY header 901 also includes HE-STF/LTF1 908for estimating the channel and decoding of HE-SIG-B 910, HE-SIG-C 912,and data payload 916 for each allocated user's stream. In case the datapayload 916 is encoded with the number of space-time streams more thanone, additional HE-LTF2 to HE-LTF2 n 914 would follow HE-SIG-C 912.

In the implementation of FIG. 9, HE-SIG-A 906 may include informationrelating to proper channel deferral and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, BSS Color, group ID and/or partial AID/BSSID of target STAs,GI (Guard Interval), and frequency domain tone spacing in the event thatthere is more than one frequency domain tone spacing used in the frame.HE-SIG-A 906 may also include an indication as to whether HE-SIG-B 910exists in PHY header 901. In one implementation, HE-SIG-B 910 may have avariable size and HE-SIG-A 906 may indicate a length of HE-SIG-B 910.For example, if HE-SIG-A 906 indicates that the length of HE-SIG-B 910is zero, HE-SIG-B 910 is not included in PHY header 901. However, ifHE-SIG-A 906 indicates that the length of HE-SIG-B 910 is a number otherthan zero, PHY header 901 will include HE-SIG-B 910 of the lengthindicated. In another implementation, HE-SIG-B 910 may have a fixedlength and a single bit in HE-SIG-A 906 may indicate whether or not PHYheader 901 includes HE-SIG-B 910.

HE-SIG-A 906 is encoded in a predetermined channel bandwidth, e.g. 20MHz, and is duplicated at every predetermined channel bandwidth that theframe occupies. Also, channel estimation and decoding of HE-SIG-A 906may rely on L-STF/L-LTF 902. HE-SIG-B 910 has the resource allocationinformation for each scheduled STA, which may include mappinginformation between allocated sub-channel and corresponding STA.HE-SIG-B 910 may be encoded using an entire bandwidth that is indicatedin HE-SIG-A 906 or may be encoded across multiple sub-bands of thechannel in duplicated, non-duplicated, or partially duplicated parts asnoted above.

HE-SIG-C 912 may include per-STA frame information, such as MCS level,coding scheme, and/or use of STBC. In one implementation, HE-SIG-C 912may be encoded per each allocated sub-channel and utilizes HE-STF/LTF1908 for channel estimation and decoding.

For proper decoding of HE-SIG-B 910, HE-SIG-C 912 and data payload,HE-STF/LTF1 908 is included in PHY header 901 before HE-SIG-B 910. Incase the data payload is encoded with the number of space-time streamsmore than one, additional HE-LTF2 to HE-LTF2-n 914 would follow HE-SIG-C912. In case data payload of different users is encoded with differentnumber of space-time streams, the number of HE-LTF2 914 fields for eachdifferent sub-channel can be different depending on the actual number ofspace-time streams allocated in each sub-channel. If frequency domaintone spacing of data payload is different from that of legacy fields,for example legacy field is using 64 FFT in 20 MHz bandwidth (i.e., aDFT period of 3.2 μs and subcarrier spacing of 312.5 kHz) and datapayload is using 256 FFT in 20 MHz bandwidth (i.e., a DFT period of 12.8μs and subcarrier spacing of 78.125 kHz), frequency domain tone spacingof data payload is applied from HE-STF/LTF1 908 through the end of theframe.

FIG. 10 presents PHY frame 1000 having PHY header 1001 with three (3)SIG fields 1004/1006/1010 and common HE-STF/LTF1 1008 field, accordingto one implementation of the present disclosure. As shown in FIG. 10,SIG fields include L-SIG 1004, HE-SIG-A 1006 and HE-SIG-B 1010. In theimplementation of FIG. 10, HE-SIG-A 1006 includes an indication to areceiver whether or not HE-SIG-B 1010 includes resource allocationinformation. As such, resource allocation information is included inHE-SIG-B 1010 only when HE-SIG-A 1006 indicates that HE-SIG-B 1010includes such information. As shown in FIG. 10, PHY header 1001 alsoincludes L-STF/L-LTF 1002 and L-SIG 1004, which are the same as L-STF302, L-LTF 304 and L-SIG 306 in PHY header 301 of FIG. 3. PHY header1001 also includes HE-STF/LTF1 1008 for estimating channel and decodingof HE-SIG-B 1010 and data payload for each allocated user's stream. Incase the data payload is encoded with a number of space-time streamsmore than one, additional HE-LTF2 to HE-LTF2-n fields 1012 would followHE-SIG-B 1010.

In the implementation of FIG. 10, HE-SIG-A 1006 may include informationrelating to proper channel deferral and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, BSS Color, group ID and/or partial AID/BSSID of target STAs,GI (Guard Interval), and frequency domain tone spacing in the event thatthere is more than one frequency domain tone spacing used in the frame.HE-SIG-A 1006 may also include an indication if HE-SIG-B 1010 includesresource allocation information, and may also indicate the size ofHE-SIG-B 1010.

HE-SIG-A 1006 is encoded in a predetermined channel bandwidth, e.g. 20MHz and is duplicated at every predetermined channel bandwidth that theframe occupies. Also, channel estimation and decoding of HE-SIG-A 1006may rely on L-STF/L-LTF 1002. HE-SIG-B 1010 may include per-STA frameinformation, such as MCS level, coding scheme, and/or use of STBC. IfHE-SIG-A 1006 indicates that HE-SIG-B 1010 includes resource allocationinformation, HE-SIG-B 1010 field will have resource allocationinformation for each scheduled STA, which may include mappinginformation between allocated sub-channel and corresponding STA.HE-SIG-B 1010 may be encoded using an entire bandwidth that is indicatedin HE-SIG-A 1006 or may be encoded across multiple sub-bands of thechannel in duplicated, non-duplicated, or partially duplicated parts asnoted above.

For proper decoding of HE-SIG-B 1010 and data payload, HE-STF/LTF1 1008is included in PHY header 1001 before HE-SIG-B 1010. In case the datapayload is encoded with the number of space-time streams more than one,additional HE-LTF2 to HE-LTF2-n 1012 would follow HE-SIG-B 1010. Iffrequency domain tone spacing of data payload is different from that oflegacy fields, for example legacy field is using 64 FFT in 20 MHzbandwidth (i.e., a DFT period of 3.2 μs and subcarrier spacing of 312.5kHz) and data payload is using 256 FFT in 20 MHz bandwidth (i.e., a DFTperiod of 12.8 μs and subcarrier spacing of 78.125 kHz), frequencydomain tone spacing of data payload is applied from HE-STF/LTF1 1008through the end of the frame.

In another implementation that is shown in FIG. 10, HE-SIG-A 1006 mayinclude an indication to a receiver whether HE-SIG-B 1010 is included inPHY header 1001 or not, where HE-SIG-B 1010 includes resource allocationinformation. As such, resource allocation information is included inHE-SIG-B 1010 only when HE-SIG-A 1006 indicates that HE-SIG-B 1010 isincluded in PHY header 1001. As shown in FIG. 10, PHY header 1001 alsoincludes L-STF/L-LTF 1002 and L-SIG 1004, which are the same as L-STF302, L-LTF 304 and L-SIG 306 in PHY header 301 of FIG. 3. PHY header1001 also includes HE-STF/LTF1 1008 for estimating channel and decodingof HE-SIG-B 1010 and data payload for each allocated user's stream. Incase the data payload is encoded with a number of space-time streamsmore than one, additional HE-LTF2 to HE-LTF2-n fields 1012 would followHE-SIG-B 1010.

In this implementation of FIG. 10, HE-SIG-A 1006 may include informationrelating to proper channel deferral, and overall frame formatinformation, which may include channel bandwidth, basic service set(BSS) ID, BSS Color, group ID and/or partial AID/BSSID of target STAs,GI (Guard Interval), and frequency domain tone spacing in the event thatthere is more than one frequency domain tone spacing used in the frame.HE-SIG-A 1006 may also include an indication as to whether HE-SIG-B 1010exists in PHY header 1001. In one implementation, HE-SIG-B 1010 may havea variable size, and HE-SIG-A 1006 may indicate a length of HE-SIG-B1010. For example, if HE-SIG-A 1006 indicates that the length ofHE-SIG-B 1010 is zero, PHY header 1001 will not include HE-SIG-B 1010.However, if HE-SIG-A 1006 indicates that the length of HE-SIG-B 1010 isa number other than zero, PHY header 1001 will include HE-SIG-B 1010 ofthe length indicated.

HE-SIG-A 1006 may be encoded in a predetermined channel bandwidth, e.g.20 MHz, and may be duplicated at every predetermined channel bandwidththat the frame occupies. Also, channel estimation and decoding ofHE-SIG-A 1006 may rely on L-STF/L-LTF 1002. HE-SIG-B 1010 may includeper-STA frame information, such as MCS level, coding scheme, and/or useof STBC. HE-SIG-B 1010 field may also have resource allocationinformation for each scheduled STA, which may include mappinginformation between allocated sub-channel and corresponding STA.HE-SIG-B 1010 may be encoded using an entire bandwidth that is indicatedin HE-SIG-A 1006 or may be encoded across multiple sub-bands of thechannel in duplicated, non-duplicated, or partially duplicated parts asnoted above.

For proper decoding of HE-SIG-B 1010 and data payload, HE-STF/LTF1 1008may be included in PHY header 1001 before HE-SIG-B 1010. In case thedata payload is encoded with the number of space-time streams more thanone, additional HE-LTF2 to HE-LTF2-n 1012 would follow HE-SIG-B 1010. Iffrequency domain tone spacing of data payload is different from that oflegacy fields, for example legacy field is using 64 FFT in 20 MHzbandwidth (i.e., a DFT period of 3.2 μs and subcarrier spacing of 312.5kHz) and data payload is using 256 FFT in 20 MHz bandwidth (i.e., a DFTperiod of 12.8 μs and subcarrier spacing of 78.125 kHz), frequencydomain tone spacing of data payload is applied from HE-STF/LTF1 1008through the end of the frame.

FIG. 11 presents a flow diagram of method 1100 for use by a wirelessdevice in WLAN 110 of FIG. 1, according to one implementation of thepresent disclosure. For example, method 1100 may be performed by AP 102or STA 104. Method 1100 will be described below in relation to AP 102for simplicity, but it is understood that method 1100 may be similarlyperformed by another wireless device in WLAN 110.

As discussed above and shown in FIG. 2, AP 102 may include basebandprocessor 202 and memory 240, which may be used to perform one or moreof the operations of method 1100. In one embodiment, method 1100 maycommence at operation 1110. At operation 1110, AP 102 may determinewhether resource allocation/scheduling information should or needs to beincluded in a generated frame that will be transmitted to one or morerecipients by AP 102. In one embodiment, AP 102 may determine atoperation 1110 that the resource allocation/scheduling information isunnecessary for the generated frame when the generated frame is intendedto be sent to a single recipient in a full-band transmission (e.g., asingle user (SU) full band transmission). In this case of a singlerecipient/user full band transmission, resource allocation/schedulinginformation provided would be unnecessary as the channel will not bedivided into separate sub-channel/resource units. When method 1100 willbe performed by STA 104, the resource allocation/scheduling informationmay be unnecessary when the generated frame will be transmitted as aresponse to a trigger frame. In the case of a response to a triggerframe, resource allocation/scheduling information does not need to beretransmitted back to the sender of the trigger frame as the triggerframe included this information. Accordingly, the recipient of thegenerated frame would already be aware of this reallocation information.Conversely, resource allocation/scheduling information may be necessarywhen the generated frame is a downlink multi-user transmission (e.g., anOFDMA transmission from AP 102 to two or more STAs 104/106/108). In thissituation, each STA needs to know sub-channel assignment to analyze thegenerated frame, which would be provided in resourceallocation/scheduling information.

In response to determining that the resource allocation/schedulinginformation is needed in the generated frame, operation 1120 may set anindication in a first signaling field of the generated frame that asecond signaling field containing the resource allocation/schedulinginformation is present in the generated frame. In one implementation,this indication may be a single bit that indicates the presence of thesecond signaling field, while in other implementations the indicationmay be a series of bits that indicates a length of the second signalingfield. For example, in the latter case, the first signaling field mayrecord a length of zero when the second signaling field is not presentand a length greater than zero when the second signaling field ispresent.

In some embodiments, the generated frame may be similar or identical toone or more of frames 500/600/700/750/800/900/1000 described above andmay include a header similar to one or more of headers501/601/701/751/801/901/1001. For example, the first signaling field maybe HE-SIG-A while the second signaling field is HE-SIG-B.

Following setting the indication of the presence of the second signalingfield and corresponding presence of resource allocation/schedulinginformation, operation 1130 may add the second signaling field to theframe. As noted above, the second signaling field may include resourceallocation/scheduling information, including mapping of STAs toparticular sub-bands of a channel.

Returning to operation 1110, upon determining that resourceallocation/scheduling information is not needed in the frame, operation1130 may reflect this decision in the first signaling field. As notedabove, when method 1100 is being performed by STA 104 and the generatedframe is a response to a trigger frame, the frame may not requireresource allocation/scheduling information. In particular, since thetrigger frame already included resource allocation/schedulinginformation, the generated frame does not need to convey thisinformation to the original sender (e.g., AP 102).

Although described in relation to first and second signaling fields, thegenerated frame may include one or more additional fields, such asL-STF/LTF 502/602/702/752/802/902/1002 and L-SIG504/604/704/754/804/904/1004, HE-STF/LTF 512/610/712/758/810/914/1012and HE-SIG-C 514/612/912, and also data payload522/614/714/760/812/916/1014. Following generation of the generatedframe, AP 102 may transmit the generated frame at operation 1140 to oneor more wireless devices (e.g., STAs 104/106/108).

Turning now to FIG. 12, method 1200 will be described. Method 1200 maybe performed by a wireless device operating in WLAN 110 shown in FIG. 1.For example, method 1200 may be performed by AP 102 or STA 104. Asdescribed herein, method 1200 will be performed by STA 104 forsimplicity of description. As discussed above and shown in FIG. 2, STA104 may include baseband processor 202 and memory 240, which may be usedto perform one or more of the operations of method 1200.

Method 1200 may commence at operation 1210 with STA 104 receiving aframe, which may have been generated by AP 102 using method 1100. Theframe may include a first signaling field and optionally a secondsignaling field, which contains resource allocation information formultiple user transmissions. In some embodiments, the received frame mayalso be received simultaneously by multiple other STAs (e.g., STA 106and 108).

At operation 1220, STA 104 may process the received frame. Processingthe frame may include analyzing a first signaling field of the firstframe to determine the presence of a second signaling field. Asdescribed above in relation to method 1100, the first signaling fieldmay include an indication as to whether a second signaling fieldcontaining resource allocation information is present in the receivedframe. This indication may be a single bit or a set of bits, which maybe used to indicate the length of the second signaling field.

Upon determining that the second signaling field is present and/orincludes resource allocation information, STA 104 may extract resourceallocation information from the second signaling field of the receivedframe at operation 1230. STA 104 may thereafter utilize the extractedinformation to process the frame at operation 1240. For example, STA 104may determine a sub-band/sub-channel in the frame that isdevoted/assigned/mapped to STA 104 based on the extracted resourceallocation information from the frame. For example, the resourceallocation information may indicate that a 20 MHz channel, upon whichthe received frame was transmitted, has been divided into twosub-channels/sub-bands: a first sub-channel/sub-band mapped to STA 104and a second sub-channel/sub-band mapped to STA 106. In this example,STA 104 may analyze the resource scheduling information and determinethat the first sub-channel/sub-band is mapped to STA 104. Based on this,STA 104 may process a data payload of the frame transmitted within thefirst sub-channel/sub-band.

Alternatively, upon determining that the second signaling field is notpresent and/or the received frame does not include resource allocationinformation, STA 104 may process the frame using previously knownresource allocation information at operation 1250 or otherwise withoutresource allocation information from the received frame (e.g., processthe frame a single user, full band transmission).

From the above description it is manifest that various techniques can beused for implementing the concepts described in the present applicationwithout departing from the scope of those concepts. Moreover, while theconcepts have been described with specific reference to certainimplementations, a person of ordinary skill in the art would recognizethat changes can be made in form and detail without departing from thescope of those concepts. As such, the described implementations are tobe considered in all respects as illustrative and not restrictive. Itshould also be understood that the present application is not limited tothe particular implementations described above, but many rearrangements,modifications, and substitutions are possible without departing from thescope of the present disclosure.

As noted above, an embodiment of the invention may be an apparatus(e.g., an access point, a client station, or another network orcomputing device) that includes one or more hardware and software logicstructure for performing one or more of the operations described herein.For example, the apparatus may include a memory unit, which storesinstructions that may be executed by a hardware processor installed inthe apparatus. The apparatus may also include one or more other hardwareor software elements, including a network interface, a display device,etc.

As also noted above, an embodiment of the invention may be an article ofmanufacture in which a machine-readable medium (such as microelectronicmemory) has stored thereon instructions which program one or more dataprocessing components (generically referred to here as a “processor”) toperform the operations described above. In other embodiments, some ofthese operations might be performed by specific hardware components thatcontain hardwired logic (e.g., dedicated digital filter blocks and statemachines). Those operations might alternatively be performed by anycombination of programmed data processing components and fixed hardwiredcircuit components.

What is claimed is:
 1. A method for performing wireless communications,the method comprising: receiving, by a wireless device, a trigger framethat coordinates an uplink multiuser transmission; generating, by thewireless device, an uplink frame, wherein generating the uplink frameincludes: providing, in the uplink frame, a High Efficiency Signal A(HE-SIG-A) field including frame format information for the uplinkframe, and providing, in the uplink frame, a High Efficiency ShortTraining Field (HE-STF) immediately after the HE-SIG-A field in responseto receiving the trigger frame; and transmitting, by the wireless deviceas an immediate response to the trigger frame, the uplink frame over awireless channel.
 2. The method of claim 1, wherein generating theuplink frame further includes: providing a High Efficiency Long TrainingField (HE-LTF) immediately after the HE-STF.
 3. The method of claim 1,wherein the wireless channel includes a plurality of resource unitsassigned to one or more wireless devices, and wherein generating theuplink frame further includes: providing the HE-SIG-A field in each 20MHz channel of the wireless channel, and providing the HE-STF and theHE-LTF in each assigned resource unit of the wireless channel.
 4. Themethod of claim 3, wherein the trigger frame includes resourceallocation information, and wherein the wireless device transmits theuplink frame using a resource unit assigned to the wireless device inthe trigger frame.
 5. The method of claim 1, wherein generating theuplink frame includes: providing, using the HE-SIG-A field, anindication that an HE-SIG-B field is not present in the uplink frame. 6.The method of claim 5, wherein the HE-SIG-A field includes a lengthsub-field that indicates a length of the HE-SIG-B field.
 7. The methodof claim 6, further comprising: setting the length sub-field to zero inresponse to receiving the trigger frame.
 8. The method of claim 5,wherein the HE-SIG-B field includes scheduling information forprocessing a corresponding frame by a receiving device.
 9. The method ofclaim 8, wherein the scheduling information includes a mapping ofresource units to stations.
 10. The method of claim 1, wherein the frameformat information includes channel bandwidth information and basicservice set (BSS) Color or information on a BSS identification for thewireless device.
 11. The method of claim 1, wherein the uplink frame isone or more of a Multi-User Up-Link Orthogonal Frequency DivisionMultiple Access (MU UL OFDMA) frame and a Multi-User Up-Link Multi-UserMultiple Input Multiple Output (MU UL MIMO) frame.
 12. A method forperforming wireless communications in a wireless network, the methodcomprising: generating, by a wireless device, a frame, whereingenerating the frame includes: determining that the frame is intendedfor a single recipient station; providing, in the frame, a HighEfficiency Signal A (HE-SIG-A) field including frame format informationfor the frame, providing, in the frame, an address of the singlerecipient station in the wireless network, and providing, in the frame,a High Efficiency Short Training Field (HE-STF) immediately after theHE-SIG-A field in response to determining that the frame is intended forthe single recipient station; and transmitting, by the wireless device,the frame over a wireless channel to the single recipient station. 13.The method of claim 12, wherein generating the frame further includes:providing a High Efficiency Long Training Field (HE-LTF) immediatelyafter the HE-STF.
 14. The method of claim 12, wherein generating theframe further includes: providing the HE-SIG-A field in each 20 MHzchannel of the wireless channel, and providing the HE-STF and the HE-LTFacross an entire bandwidth of the wireless channel.
 15. The method ofclaim 12, wherein generating the frame includes: providing, using theHE-SIG-A field, an indication that the HE-SIG-B field is not present inthe frame.
 16. The method of claim 15, wherein the HE-SIG-A fieldincludes a length sub-field that indicates a length of the HE-SIG-Bfield.
 17. The method of claim 12, wherein the frame format informationincludes channel bandwidth information, cyclic prefix, and basic serviceset (BSS) Color or information on a BSS identification for the wirelessdevice.
 18. A wireless device for performing wireless communications ina wireless network, the wireless device comprising: one or morememories; and one or more processors coupled to the one or morememories, the one or more processors configured to generate a frame fortransmission, wherein generating the frame includes: determining thatthe frame is intended for a single recipient station; providing, in theframe, a High Efficiency Signal A (HE-SIG-A) field including frameformat information for the frame, providing, in the frame, an address ofthe single recipient station in the wireless network, and providing, inthe frame, a High Efficiency Short Training Field (HE-STF) immediatelyafter the HE-SIG-A field in response to determining that the frame isintended for the single recipient station; and transmitting, by thewireless device, the frame over a wireless channel to the singlerecipient station.
 19. The wireless device of claim 17, whereingenerating the frame includes: providing, using the HE-SIG-A field, anindication that the HE-SIG-B field is not present in the frame.
 20. Thewireless device of claim 19, wherein the HE-SIG-A field includes alength sub-field that indicates a length of the HE-SIG-B field.